NOISE levels generated by planes flying into Birmingham Airport have fallen to their lowest level since records began, say its bosses.

They say that better engineering and millions of pounds which has been invested in insulating homes has helped to slash complaints about loud flights.

The airport also said it expected noise to fall further with the introduction of quieter models of planes and vowed to continue hitting airlines which broke strict noise limits with fines.

But residents at a meeting said their homes were being shaken at night by ageing military planes flying an increasing number of injured troops in to the city from Afghanistan for treatment at Selly Oak Hospital.

Kirstin Kane, environment monitoring officer for the airport, said the venue was doing all it could to mitigate noise but some matters were outside of its control. She said: “We are now at our lowest noise levels since 1993 when our records started.

“We are working with the airlines and in discussion with individual captains to help to reduce levels further. Unfortunately we have no control over military planes coming in to bring soldiers to Selly Oak Hospital.”

Figures show that less than 25,000 people are “significantly impacted” by the levels of noise at the airport – compared to almost 90,000 in 1993. The statistics are included in Birmingham Airport’s draft Noise Action Plan for 2010 until 2015, which is currently out for consultation with residents in affected areas of the Midlands including Shard End, Balsall Common, Catherine de Barnes and Hampton in Arden. The document sets out an ongoing commitment to restrict the numbers and types of plane that can use the runway at night and impose charges on airlines responsible for breaking sound limits. But the drive to reduce noise has come at a cost for the airport, which has lost business to East Midlands Airport where no restrictions have been placed on night flying.